Network systems using virtualization technology in the related art may virtually isolate hardware resources using the virtualization technology disclosed in Non-Patent Literature 1, and generate slices which are virtual networks logically generated on a network infrastructure. Services are allocated to the slices, and thus services can be provided using networks of slices which are independent of each other. Thereby, in a case where slices are allocated to each of services having a diversity of request conditions, it is made easy to satisfy the requested conditions of individual services, and thus it is possible to reduce the amount of signaling processes thereof or the like.